Reduce minimum size of Panels to allow 1-text-line tight autosize.

chrome/test/data/extensions/api_test/window_update/show_state/test.html

 <script>
 var pass = chrome.test.callbackPass;
 
 var width = 0;
 var height = 0;
 var changedWidth = 500;
 var changedHeight = 500;
 
 function checkRestoreWithBounds(theWindow) {
   chrome.test.assertEq('normal', theWindow.state);
@@ skipping 40 matching lines @@
 }
 
 function minimizeWindow(theWindow) {
   chrome.test.assertEq('normal', theWindow.state);
   width = theWindow.width;
   height = theWindow.height;
   chrome.windows.update(theWindow.id, {'state': 'minimized'}, pass(checkMinimized));
 }
 
 function testWindowState(windowType) {
-  chrome.windows.create({'url': 'hello.html', 'type': windowType},
+  // Specifying size prevents 'panel' windows from computing size asynchronously. It ensures
+  // panel sizes stay fixed through the test.
+  chrome.windows.create({'url': 'hello.html', 'type': windowType, 'width':100, 'height':100 },
     pass(minimizeWindow));
 }
 
 chrome.test.runTests([
   function changeWindowState() {
     testWindowState('normal');
   },
   function changePopupWindowState() {
     testWindowState('popup');
   },
   function changePanelWindowState() {
     testWindowState('panel');
   }
 ]);
 </script>